The invention generally relates to an apparatus capable of tightening a seat belt about an occupant. These apparatuses are typically called pretensioners or belt tighteners.
During a vehicle crash event, it may be desirable to tighten the seat belt, i.e. to remove slack, about the occupant prior to the time the occupant begins to move forward. The typical prior art buckle pretensioner or belt tightener utilizes a cable secured between the buckle frame and a movable piston. Upon activation of the belt tightener, the piston is urged down a tube thereby pulling the buckle toward the vehicle floor to eliminate a predetermined amount of slack, typically 100-110 millimeters, in the seat belt relative to the occupant.
It is an object of the present invention to provide a belt tightening apparatus having a relatively small size. A further object of the present invention is to provide a belt tightener in which a flexible member such a length of seat belt webbing is drawn into the housing of the belt tightener to remove slack.
Accordingly the invention comprises: a belt tightening device for use with a safety device such as a seat belt buckle, a flexible member such as a length of seat belt webbing, operatively connected to the safety device; a housing including a first opening through which the flexible member loosely extends; a first and second relatively movable clamping members for causing a portion of the flexible member extending from the housing to be drawn into the housing thereby shortening the remaining length of the flexible member belt causing a safety belt operatively attached to or part of the flexible member to become more tightly disposed about a user thereof. More particularly, the present invention changes the shape of the flexible member from that of straight to corrugated or pleated and in so doing foreshortening an extending, adjacent section of the flexible member. Various other embodiments are described.
Many other objects and purposes of the invention will be clear from the following detailed description of the drawings.